Straight and level flight Flashcards
what is weight?
the force that acts from the CoG towards the centre of the earth.
what is lift?
the force that opposes weight in straight and level flight. what keeps the aircraft in the air
lift and weight form what?
a couple. Two ewual and opposite forces that act about a central pivot point.
like string, pull on them and the nose of the aircraft pitch down so this couple can be called nosedown couple
what is thrust?
the force that propels an aircraft through the air.
what is drag?
the force opposing thrust. opposes motion and slows an aircraft down.
thrust and drag form what?
a couple. meaning if you pull on them like string nose of the aircraft pitch up so we call this a pitch up couple
if one couple produces a stronger moment force than the other what happens?
will cause a change in the pitch of the aircraft.
what is pitching moments?
a leftover since these two couples are not always equal and opposite. these pitching moments are either nose up or down.
what is longitudinal stability?
stability in pitch. an aircraft that is longitudinally stable returns to its original position when disturbed in pitch.
what is longitudinal dihedral?
when the tailplane is set at a lower angle of incidence of the wing.
with the angle of incidence being the angle that the tailplane or wing is set relative to the fuselage.
if the aircraft was upset in pitch upwards by 2 degrees in longitudinal dihedral what would happen to the AoA and what would this mean?
AoA would increase by 50% whereas the tailplane would see an increase of 100%.
tail section would proportionally produce more lift, raising the tail, thereby restoring the aircraft back to OG positon
the restoring moment provided by the tailplane is greater when?
if the distance between the tailplane and the CoG is increased.
what is the relationship between the CoG and CoP? (example aircraft is upset in pitch and pitches up)
- lift force is increased because AoA is increased, and CoP will move forwards.
the arm between the two decreases, the additional increase in lift force is enough to cause the nose to return to the original position.
what is the simplified lift formula?
lift = AoA x IAS
what is the relationship between the simplified lift formula?
if airspeed reduces, AoA must increase to maintain a constant amount of lift. The nose attitude and AoA will be higher aswell, and so for the inverse.
